pretty dumb but
Originally in the draft there’s a scene in the movie where we see David with his headset on and he’s talking to someone, and we don’t know who it is, and he gets confronted by Vickers [Charlize Theron]. There’s a scene in the script that we decided not to shoot, where we see the inside of that dream, and basically David takes a jet ski out with a beautiful woman in a bikini, to a yacht, and on the yacht is Weyland – played by Guy, without old-age make-up: this is his dream. They have a scene together and in it David says, “The engineers are dead, they’re all gone, mission failure,” and Weyland says, “Go back and try harder.” We rewrote it so that we were going to play Weyland’s identity closed, give the audience a sense that David was talking to someone on the ship but not view them.
But we had already shot the scenes with Guy in the old-age make-up. So we were like, "Are people are going to wonder why we cast Guy Pearce to play an old man, unless we represent him as Guy Pearce?" So that basically tapped into a piece of viral we had already been talking about, which is that I said it would be really cool to introduce the title of the movie – because people were asking “Prometheus, what is that?”, “How does the myth have context in the context of this movie?” So I said we should write this TED talk, and then Ridley basically handed it off to Luke, his son, who is an incredible director, and we got together with Tom Rielly at TED and said, “Can we use your branding?” because if we can’t call it a TED talk we’ll have to call it a “FRED talk” or something. Everyone will know, it’ll cheapen it.